Many sports require the hitting of a ball during play, and therefore much time is spent in the practice of this aspect of said sports. One method of intensive practice is to use a device to hold the ball at the proper height, allowing the player to strike it. Several devices are described in the prior art including U.S. Pat. Nos. 3,166,317, 3,301,556, 3,006,647, and 3,367,655, and typically comprise a ball tethered at the proper height by means of a cord attached to a cross arm of the device. After being struck, the ball will travel in a looping path, finally stopping at its initial location positioned to be struck again.
Such a device could be used in the practice of tennis, but several problems inherent to the practice of tennis tend to diminish the usefulness of these devices. One problem is that accuracy is much more important in tennis than baseball, for instance, so that a person practicing tennis must know exactly where the ball would go if struck. Since the prior art devices have the ball permanently attached to a cord, the player cannot know what the trajectory of the ball would have been. In a tennis trainer, the ball must detach from the fastening means when hit.
A second characteristic of tennis is that the practicing of ground strokes, serves and overhead smashes require that the ball be suspended anywhere from just above ground level to as much as ten feet high. The cross arm must be higher than that, putting it completely out of reach. Therefore, if the cord wraps or tangles on the cross arm, the disentangling of it becomes a time consuming process.
Another problem for a tennis trainer used for serving practice is that the ball holding means is also out of reach. Therefore, some convenient means must be provided for the lowering of the ball holding means between serves so that it can be reloaded.
Further, a device which overcomes the specific problems related to the practice of tennis must still be designed to be manufactured economically in commercial quantities.
Of particular importance in a tennis trainer is the means for connecting the ball to the cord. The ball must be held just well enough to prevent the ball from disengaging before being struck, but the connection must not be so strong that any significant force is exerted on the ball by the cord at the time of impact which would alter its trajectory.
Another frequent requirement in tennis is to hold a second ball when a first ball is in play. It would be a convenience if the means for connecting the ball to the tennis trainer cord could be adapted to be used for temporarily securing a second tennis ball to the belt of the player, allowing hands-free retention of the second ball during play.
I have previously discovered that instruction in another sport, namely volleyball, is greater facilitated by devices which eliminate toss function so the player may concentrate on his own motions without being disturbed by the variations in the toss by oneself or another players. Such teaching devices are disclosed in my patents.